. >> a developing story, a health scare for vice president joe biden's son. why he is undergoing tests and the medical history that could have doctors concerned. >> an addition to the first family. see the obama's new, adorable puppy. >> america's favorite mini-commander-in-chief. landing a big scoop and pretty coveted kiss. all ahead in "the skinny." it's tuesday, august 20th. >> announcer: from abc news, this is "world news now" with john muller and diana perez. >>> good tuesday morning. we are going to begin this half-hour with news of a significant arrest in egypt. spiritual leader of the muslim brotherhood in police custody. >> this comes as the u.s. is considering its options in the region. abc's karen travers joining us from washington with more on this. >> reporter: good morning, diana. good morning, john. secretary of defense chuck hagel admitted yesterday there isn't much the u.s. can do right now. this is up to the egyptian people. an uneasy calm in egypt, a break from the horrific violence last week. but a brazen daylight attack in the sinai penin